1. Technical Field
The present invention is directed towards skincare compositions. More particularly, the present invention is directed towards sunscreen compositions having improved efficacy in protection from ultraviolet radiation.
2. Background Information
Consumers are increasingly concerned about the effects of ultraviolet (‘UV’) radiation on the skin, and with good reason. Skin cancer has become one of the leading forms of cancer, annually affecting millions globally. Demand for UV protection has made the sun care market one of the fastest growing personal care sectors.
Commercially viable sun care products should provide a variety of benefits, such as high Sun Protection Factor (SPF) values, protection from UV-A and UV-B radiation (also known as broad-spectrum protection), water resistance and rub-off resistance, aesthetically pleasing products, and convenient application.
When formulating these products, consumer use should be considered. For example, swimming or mild perspiration is often sufficient to remove most commercially available sunscreen formulations from a person's skin, necessitating multiple applications. Such repeated applications are inconvenient, costly and typically results in the consumer delaying reapplication of the sunscreen, which may lead to sunburn.
Accordingly, higher SPF values, broad spectrum protection, enhanced water and rub-off resistance, the need for aesthetically pleasing products, and convenience have become increasingly important in sun protection formulations. Further, formulators continue to search for ways to not only increase the SPF value of formulations, but also to increase the efficacy of a sunscreen without increasing the actual level of the sunscreen actives within the formulation.
Additionally, formulators are left with little choice in the type of rheology modifiers used in formulations, particularly those containing actives (or agents) such as inorganic particulate sunscreen agents. Historically, xanthan gum has been the thickener of choice; however, this thickener contributes no benefit with respect to SPF enhancement.
Film forming polymers are used widely in personal care products for functions such as hair fixatives, SPF retention, water resistance, rub-off resistance, fragrance retention, and so forth and are well known in the art. These polymers can be both synthetic and naturally derived. The polymers are typically used in a variety of applications, including sun protection, to enhance the water and rub-off resistance of the UV filters. With the advent of higher SPF products, the challenge has been to create these sun protection formulations without increasing either the use level of the polymer or UV filters or both. Doing so causes unpleasant aesthetics and increased cost.
Therefore, there is a need for a sunscreen formulation that provides both water resistance and higher SPE values when applied to a person, both before and after immersion in water, in particular, one that provides these benefits without the need to increase the amount of sunscreen active or agent.